PB2491: LANGERHANS CELL HISTIOCYTOSIS (LCH) IN THE MAXILLOFACIAL AREA IN ADULT. COMPLETE REMISSION WITH CLADRIBINE. CASE REPORT AND REVIEW.
Authors: Dunia De Miguel Llorente, Nuria Golbano López, Ana Belen Santos Montero, Rocio Perez Alonso, Alejandro Vazquez Ramo, Helga Guillen García, Angela Gil Perez, Marta Mora Argumanez, Irene Nuevo Lopez
Journal: HemaSphere (2023)

Topic: 23. Hematopoiesis, stem cells and microenvironment Background: Langerhans cell histiocytosis (LCH) is a disease of unknown etiology, characterized by proliferation of pathological Langerhans cells within different organs. It mainly affects children, but adult cases also occur, with an incidence rate of one to two per million. The head and neck are affected in almost 90% of cases. Diagnosis is made by means of histopathological analysis, and imaging studies are necessary to determine extent of the disease. There are no controlled trials proposing an optimal treatment protocol for LCH. Prognosis in adults is generally good due to the slow evolution of the disease and its favorable response to treatment. Aims: To report our experience with cladribine in a relapsed adult patient diagnosed of LCH. Methods: A 44-year-old male with previous history of secondary panhypopituitarism in 2011. In June 2017, he presented a right jaw`s pain. An orthopantomogram showed extensive bone loss, involving right maxillary. The lesion was resected, and the histopathological report revealed LCH. PET-CT showed no other lesions, only low SUVmax in right maxillary Bone marrow biopsy and Flow cytometry no showed infiltration by LCH. With diagnosis of LCH with multisystem damage of low risk, he was treated with vinblastine and prednisone (Therapy prolongation improves outcome in multisystem Langerhans cell histiocytosis, Trial No. NCT00276757 www.ClinicalTrials.gov). He received 6 weeks of induction cycles January-February 2018) and 12 cycles of consolidation, he was in Complete remission (CR). In January 2020, on the orthopantomogram, new radio-lucid lesions were observed in the same right jaw. The patient received prednisone for three weeks, with sort clinical response. In October 2020, he began methotrexate 20 mg/week until June 2021. This therapy was discontinued by gastrointestinal effects. In September 2021, he showed new lesions in PET and pain in jaw. We initiated treatment again with methotrexate until March 2022. In this moment, PET was in CR. Results: RESULTS: In September 2022, he presented pain in the same site. Report of PET showed a lytic lesion in right and left jaw (SUVmax 5.52 and 9.84, respectively). To avoid local toxicity with local radiotherapy, we proposed systemic treatment with cladribine (5 mg/m2 or 0.14 mg/kg intravenous daily for 2 hours D1-5). Patient received antibiotic prophylaxis with cotrimoxazole and acyclovir. Evaluation was realized after 2 cycles, PET interim was in CR. Then, he received 2 additional cycles, and right now he is in CR. Any adverse effects were reported (non-neutropenia, non-febrile episode, non-alopecia). Summary/Conclusion: 1) Given the rarity of LCH, we strongly recommend protocolization of treatment. To further this end, adult patients suffering from this disease, particularly those with multiorgan affectation, should be included in clinical trials carried out by the Histiocytosis Society. 2) Single agent cladribine is an effective therapy for adults with Langerhans cell histiocytosis with a good tolerance, and fast response. Bibliography: 1.-Hazim AZ, Ruan GJ, Hu M, et al. Langerhans cell histiocytosis with lung involvement in isolation and multisystemic disease: Staging, natural history, and comparative survival. Am J Hematol 2021: 96; 1604. 2.-Goyal G, Abeykoon JP, HU M, et al. Single-agent cladribine as an effective front-line therapy for adults with Langerhans cell histiocytosis. Am J Hematol 2021: 96: E146. Keywords: Cladribine, Langerhans Cell Histiocytosis